波浪与潮流共同作用下二维泥沙数学模型

Two-dimensional mathematical model for sediment transport by waves and tidal currents

针对河口海岸地区波浪与潮流运动的特点,将波浪过程概化为潮周期中具有平均意义的波浪流要素,叠加到潮流运动方程中,以模拟长时段的水流运动及泥沙场的变化,建立了波浪与潮流联合作用下二维泥沙数学模型,包括贴体正交曲线坐标系下水流运动方程、非均匀悬沙、底沙输移方程、初始条件、边界条件、动边界技术及数值计算格式,引进前期含沙量的概念,得到了潮流挟沙能力公式,波浪作用下的挟沙能力采用窦国仁公式,浮泥挟沙能力采用罗肇森公式。计算的瓯江口、温州湾潮位过程与原型吻合良好,8个断面的46条垂线同步流速、流向过程计算值与实测值吻合较好。在此基础上,探讨了多连通域复杂边界条件下瓯江口拦门沙航槽开挖后潮流与风浪作用下悬沙、底沙与浮泥引起航槽回淤的模拟问题。

In this study, the combined actions of waves and tidal currents in estuarine and coastal areas are considered and a 2D mathematical model for sediment transport by waves and tidal currents has been established in orthogonal curvilinear coordinates. Non-equilibrium transport equations of suspended load and bed load are used in the model. The concept of background concentration is introduced, and the formula of sediment transport capacity of tidal currents for the Oujiang River estuary is obtained. The Dou Guoren formula is employed for the sediment transport capacity of waves. Sediment transport capacity in the form of mud and the intensity of back silting are calculated by using Luo Zaosen＇ s formula. The calculated tidal stages are in good agreement with the field data, and the calculated velocities and flow directions of 46 vertical lines for 8 cross sections are also in good agreement with the measured data. On such a basis, simulations of back silting after the excavation of the sand bar waterway under complicated boundary conditions in the navigation channel induced by suspended load, bed load and mud by waves and tidal currents are discussed.